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johnnie225
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The Four Truths of Digital

The Four Truths of Digital:

Truth One: DSD is a 4-8 bit recording system, not 1. This means it gets decimated and oversampled - two things the scheme was trying to avoid in the first place.

Truth Two: 16-bit "audiophile" CDs contain 20-bit level resolution and have since 1993.

Truth Three: The limit of human hearing is 20-bit level resolution.

Truth Four: Digital is hundreds of times lower in distortion vs. analog...but its distortions are spread out spectrally and are hard to pin down. They are removing these, at last, in the latest playback gear.

JPH

haroon
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Re: The Four Truths of Digital

Can you write some quality references to support each of these statements?

Regards

johnnie225
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Re: The Four Truths of Digital

I'd start with John Atkinson (concerning CD resolution) here: http://stereophile.com/asweseeit/56/index.html

At the time of this report, JA thought that the technique used to extend the resolution (on CD) applied to the "upper midrange" only. It turned out to be more.....

As for DSD, Robert Greene wrote in the June 2001 issue of The Absolute Sound concerning its recording system. Sound on Sound (U.K.) wrote on it as well in 2004. I'm sorry I don't have the exact issue - the article should be available online.

Finally, the limits of human hearing have been demonstrated by various researchers, most notably Malcolm Hawksford.

It's just sad that high-end reviewers and writers never told us these things.......

JPH

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Re: The Four Truths of Digital

Your point is?

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Re: The Four Truths of Digital

Thanks for posting, jph. I'm sure many novices will find your posts useful.

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Re: The Four Truths of Digital


Quote:
It's just sad that high-end reviewers and writers never told us these things.......


Of course ignoring those you just cited.

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Re: The Four Truths of Digital
Editor
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Re: The Four Truths of Digital


Quote:
I'd start with John Atkinson (concerning CD resolution) here: http://stereophile.com/asweseeit/56/index.html

At the time of this report, JA thought that the technique used to extend the resolution (on CD) applied to the "upper midrange" only. It turned out to be more...

As this July 1994 essay of mine concerned the then-imminent advent of lossy data compression and makes no mention of midrange resolution, I am not certain what point you are trying to make.

John Atkinson
Editor, Stereophile

Elk
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Re: The Four Truths of Digital

Ncdrawl, is your post directed at my post or simply a bunch of resources?

Just trying to understand your post.

johnnie225
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Re: The Four Truths of Digital

JA: Bottom of the first paragraph - you stated it clearly.....

If this isn't enough for naysayers, look at your (audiophile) CD liner notes. I have one from Sony Classical and it states - clearly - that they were able to preserve 20-bit sound on the 16-bit CD (using Super-Bit Mapping). And this disc dates from 1992 !!

JPH

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Re: The Four Truths of Digital

So you're talking about HDCD is this correct?

Elk
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Re: The Four Truths of Digital

Sony's Super-Bit Mapping is just Sony's trademark for its particular form of noise shaped dither.

It decidedly does not magically place 20-bits of data on a 16-bit CD.

Their marketing reference to 20-bit sound meant only that one didn't hear quantization noise on the resulting 16-bit recording, from which they argued the 16-bit sound was now somehow equivalent to 20-bit sound.

Nonsense. All dither does this; it's the very purpose of dither.

It's just dither with noise shaping - of which there are many kinds.

Big whoop.

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Re: The Four Truths of Digital

Yeah, he's wrong and I still don't see his point.

Is he dissing SACD, or saying that all we need is RBCD, or what? If so, then I don't agree, since my SACDs sound better than my RBCDs, but not by much.

Dave

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Re: The Four Truths of Digital


Quote:
JA: Bottom of the first paragraph - you stated it clearly...

My apologies, you are correct. I did indeed write "it appears likely that, in next to no time at all, all CD releases will be offering close to 20-bit resolution

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Re: The Four Truths of Digital

Elk: No-one is claiming that "extra bits" are being added to CD. CDs resolution - as we hear it - is at the 20-bit level. This is what JA was talking about and what the db specs will show.....

This helps explain why CD (now) sounds as good as - or better than - SACD. If CD was "low-rez", how could this be possible ?

JPH

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Re: The Four Truths of Digital

I'm struggling to understand what jph-22's point is. Maybe some hidden truth? Not. More like forgotten bits of trivia. (pun intended)

Here is a link to what he may be referring to:

http://en.wikipedia.org/wiki/High_Definition_Compatible_Digital

johnnie225
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Re: The Four Truths of Digital

Scott G: Not referring to HDCD. We're talking good 'ol Redbook !!

JPH

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Re: The Four Truths of Digital

So you're saying that redbook 16 bits is actually 20 bits? I'm confused.

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Re: The Four Truths of Digital


Quote:
Elk: No-one is claiming that "extra bits" are being added to CD. CDs resolution - as we hear it - is at the 20-bit level.


I addressed this: "Their marketing reference to 20-bit sound meant only that one didn't hear quantization noise on the resulting 16-bit recording, from which they argued the 16-bit sound was now somehow equivalent to 20-bit sound."

Again, noise shaped dither.

This is nothing new, has been written about, etc.

Most of us are at a loss to understand what point you are making.

One cannot fully capture full-range 20 bit sound with a 16 bit medium. If this is your claim this is incorrect.

If your point is that there are neat ways to use digital, you are absolutely correct.

dcstep
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Re: The Four Truths of Digital


Quote:

This helps explain why CD (now) sounds as good as - or better than - SACD. If CD was "low-rez", how could this be possible ?

JPH

Since when?? Not in my system. The upsampling routine of my Playback Designs MPS-5 makes RBCD sound pretty darn good, but it's still not up to SACD resolution standards in the same player.

Dave

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Re: The Four Truths of Digital

Scott G: Audiophile CDs have near 20-bit sound...and have for over 15 years. But writers never told us - they pushed for new formats before the current standard was maxed-out.

If SACD claims 20-bit resolution...but does not sound better than CD (at least through better players), then CD must have more in it than we thought. "Upsampling" does not create more resolution.

JPH

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Re: The Four Truths of Digital

Unfortunately, JA's graphs are of the Meridian 518...from many years ago. More modern re-dithering units can do better....

And CD does sound better than SACD - but through top-flight players like the Meridian 808.2 and the Chord reference series. Wes Phillips didn't really know which format was better in his review of Chord last year. Jimmy Hughes just reviewed the Audio Research player in Hi-Fi News and said CD "beat" SACD. But there are many more examples.

Finally, if CD does *not* have 16-bit-level quantization noise, then what does it have ? According to JA, 20-bit resolution. Esp. w/ re-dithering devices from the late 90's onward.

JPH

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Re: The Four Truths of Digital


Quote:
Scott G: Audiophile CDs have near 20-bit sound...and have for over 15 years.


you mean like 19 bits? How does one go about getting all those bits out of 16 redbook bits?

Quote:
But writers never told us - they pushed for new formats before the current standard was maxed-out.

Are you saying there is a conspiracy?
Who did they push?
What is maxed-out? How will we know when it is?

Are you a troll?

johnnie225
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Re: The Four Truths of Digital

Well, no-one told us about this - except JA briefly in 1994 !! So, take it as you will, but I don't like what I see.

In retrospect, I'm glad CD is now embarassing SACD...it just took a while for playback to reveal its potential.

Sending (digital playback) engineers on a wild goose chase after SACD set-back CD's timetable. The wait is over......

JPH

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Re: The Four Truths of Digital

I think if there is a problem it's in post production mix down, not the technology. Heavy compression removes all benefits available in more bits.

More samples and more bits allow for more subtle detail. Unfortunately subtle detail is the last concern when trying to create a "hit" recording.

If you want to be upset at someone you should proly be looking at the record companies or better yet the buying public. They're the ones who seem to be demanding it...

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Re: The Four Truths of Digital


Quote:
Unfortunately, JA's graphs are of the Meridian 518...from many years ago. More modern re-dithering units can do better...

The only really different noiseshaper introduced since then was Apogee UV-22 (no longer available, but duplicated by POW-R type 1), but this wasn't a noiseshaper as such but added dither just below Nyquist. In effect it was encoding the lower-level information within that dither. But all the more recent shapers I have tried are all variations on the basic types shown in my Meridian 518 review.


Quote:
Finally, if CD *does not have* 16-bit-level quantization noise, then what does it have ? According to JA, 20-bit resolution. Esp. w/ re-dithering devices from the late 90's onward.

The puzzle is that an optimally noiseshaped 16-bit version of a hi-rez original_still_doesn't sound like the original, even though in theory it does have sufficient resolution.

I demonstrated this at the recent RMAF, playing listeners my original hi-rez files, Red Book versions that I had prepared with great care using noiseshaping, and MP3s at various bit rates. The paradox is that when I played listeners the difference signal between a hi-rez file and the Red Book version, the difference was virtually inaudible, which strongly suggests that the 2 files should sound identical. But they didn't!

John Atkinson
Editor, Stereophile

johnnie225
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Re: The Four Truths of Digital

JA: The re-dithering unit you refer to is still an improvement over the early 90's units.

Concerning the demo, how *much* better was the hi-rez version ? And how many in the group said this ? Sounding "different" doesn't say much - esp. if miking was a factor.

Finally, I agree that a true hi-rez recording should sound marginally better - probably due to higher S/N. But now were down to nuances, with some folks not hearing any difference. Each demo is different.

JPH

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Re: The Four Truths of Digital


Quote:
...The paradox is that when I played listeners the difference signal between a hi-rez file and the Red Book version, the difference was virtually inaudible, which strongly suggests that the 2 files should sound identical. But they didn't!...

Fascinating. This would seem to suggest that subtle changes (can/do) have a resonating effect. So to speak.

haroon
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Re: The Four Truths of Digital

Just adding some fun, ANALOG RULES!

At the end, all this X digital format or Y digital format still tries to approch the analog using various statistical sampling techniques.

Regards

PS: I am not Analog fan

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Re: The Four Truths of Digital


Quote:

Finally, I agree that a true hi-rez recording should sound marginally better - probably due to higher S/N. But now were down to nuances. . .

Um, correct me if I'm wrong but isn't the High end ALL ABOUT nuances? I mean even the cheapest all in one system isn't turning Barbara Streisand's voice into Barry Manilow or a violin into a flute. More "nuances" please.

johnnie225
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Re: The Four Truths of Digital

Generally speaking, high-end is not about nuances. The benefits of our technology - compared to mass-market gear - are great, to say the least. Nuances at the high-end level are sometimes tiny - with some listeners preferring demo "A" while others preferring "B". But the larger picture is much more important than that.

JPH

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Re: The Four Truths of Digital


Quote:
Generally speaking, high-end is not about nuances.

"Mister Worf, dispatch a subspace message to Admiral Hansen - We have engaged the Borg."
--Capt. Picard

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Re: The Four Truths of Digital


Quote:
Generally speaking, high-end is not about nuances. The benefits of our technology - compared to mass-market gear - are great, to say the least. Nuances at the high-end level are sometimes tiny - with some listeners preferring demo "A" while others preferring "B". But the larger picture is much more important than that.

And, if you sail far enough out, you fall off the edge of the Earth.

Elk
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Re: The Four Truths of Digital


Quote:
Generally speaking, high-end is not about nuances. . . . But the larger picture is much more important than that.


Huh?

What "larger picture" is there than greater nuance for the high-end?

I will self-proclaim: I am a nuance slut. Gather with me, my fellow nuancers!

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Re: The Four Truths of Digital

I agree, it is the little things, but sometimes we lose sight of the big picture in that if we had the "luxury" of CD Redbook in the 30's and 40's how happy would we be to have super high quality recordings of Art Tatum and the earliest Nat King Cole. There are hundreds and hundreds of great artists we suffer through with bad mono and stereo recordings, and we listen because the music matters. We cannot escape the "what if". I am so pleased that "Kind Of Blue" sounds as great as it does.

So, the glass is way more than half full for me, and until I can plunk down money for "The Eighth Wonder of the World", the Ayre monoblocks, a C5-XE, and something from Wilson I just have to "suffer?" through still remarkable 24 bit recordings shifted to RedBook.

The new government would probably tell us we really don't need those "extra bits" anyway. Hold on to your sample-rate, the new world is on the way.

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Re: The Four Truths of Digital

I tend to agree, though for me a good bit of the hobby is making existing technology sound as good as possible with the bucks I have. My vinyl setup does not sound anywhere near as good as my CD based one, but I use it to play old, no longer available records, all but 2 used, and all having surface noise, some with skips and pops and ticks, but the music on most tracks is still there.

Jim Tavegia
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Re: The Four Truths of Digital

Today at Middle School we were discussing early American technology from the likes of Bell and Edison. "99% perspiration and 1% Inspiration," from Mr. Edison.

The picture of "cylinder phonograph" came up and I thought how cool thay must have thought that was and if they could see where we are now. To us you couldn't even put fidelity in the same sentence. But, then they weren't worried about trying to hear the "gnat farts at 50 feet"! LOL So much worry and so little time.

Poor Audiophile
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Re: The Four Truths of Digital

"The new government would probably tell us we really don't need those "extra bits" anyway. Hold on to your sample-rate, the new world is on the way."
You got that right!! Hang on to your wallets as well!
Also, please excuse my ignorance, but why all the 20 bit talk?
I thought 24 bit was the ultimate?
Please keep all answers VERY simple as I'm not an engineer.
Just a lowly little audiophile.

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